Equilibria, Energetics and Elements (F325) - June 2011 Exam.

heyyy...i was wondering if someone could tell me....you know the qu where it gave you two pka values - did you have to write a word equn or a number equn or what??? Please someone shed some light pleeeeeeeeease!

Reply 2781

abcdefpd2001

7

Anyone got an unofficial mark scheme?

Reply 2782

Rosi M

11

Original post by haydyb123

I'm glad, that means my help was worthwhile which consoles me! :biggrin:

On the subject of the exam, I was stumped by the Buffers or infamous 'Magic Tang' question, I thought we were missing a piece of information. Got the last answer by complete fluke as 67.5%... messed up the Gibbs free energy, i found T delta S and then just proceeded not to find delta S from this and just substituted T delta S into the equation...

But other than that, I have no idea how i've done! Needed 86% for an A overall, doubt I got that.

It definitely was worthwhile.. i actually remembered you whilst trying to answer that question. Was thinking, ok which is the strong acid :tongue:

Magic tang.. :s-smilie:

OCR go to such extents its unbelievable! You should have seen biology.. :eek:

Spend 3/4 months revising BIOLOGY and the full paper is on sheep, lady birds, birds, cabbages, hedgehogs and why hedgehogs shouldn't be killed :eek:

and a few behaviour questions here and there with one single definition from one module.

I thought i got the last question right, got 33.7% but i've definitely missed a step if i got half of the correct answer. I have no clue what mess ive made with the free energy question. Kc question just dragged with loads to do.. btw do you know what the right answer was for Kc?

Ah im sure you've got it! :biggrin:

For me, im revising F324 for next week.. im being really optimistic and hopeful and telling myself im going to get really high in that.. wont happen really. OCR will have made an equally wierd paper.

Reply 2783

Rosi M

11

Original post by Killmepls

Tbh I thaught biology was a better paper. Look at the specimen paper for chem, it's soo easy compared to what we had to do. In this paper yesterday they braught in delta G calculations which were never seen before, buffer ratios which were never seen before and calculations where you had to construct ionic equations first. The paper had probably only 10-15 easy marks whereas other papers had 20+. In chem it's got to a point where those who don't do maths (like me) suffer . I think Jan and June where much more straightforward for the majority of the paper, maybe it's due to my weakness in maths though..

I second that :smile:

We shouldn't be put at a disadvantage because we DON'T do maths. Fair enough, maths does help but at the end of the day, we're doing chemistry. They need to realise that good chemists are allowed to be and can be terrible mathematicians!!! :tongue:

Reply 2784

sportycricketer

Original post by Rosi M

I thought i got the last question right, got 33.7% but i've definitely missed a step if i got half of the correct answer. I have no clue what mess ive made with the free energy question. Kc question just dragged with loads to do.. btw do you know what the right answer was for Kc?

Kc was 45

Reply 2785

Rosi M

11

Original post by sportycricketer

Kc was 45

omg i swear i got 6.6 or something :confused:

Oh noooo

Reply 2786

*QueenBeee

Original post by sportycricketer

Kc was 45

heyyy...i was wondering whether you could help me out?
you know the qu where it gave you two pka values - did you have to write a word equn or a number equn or what???
What did u put?
if u dont mind me asking

Reply 2787

haydyb123

9

Original post by Rosi M

It definitely was worthwhile.. i actually remembered you whilst trying to answer that question. Was thinking, ok which is the strong acid :tongue:

Magic tang.. :s-smilie:

OCR go to such extents its unbelievable! You should have seen biology.. :eek:

Spend 3/4 months revising BIOLOGY and the full paper is on sheep, lady birds, birds, cabbages, hedgehogs and why hedgehogs shouldn't be killed :eek:

and a few behaviour questions here and there with one single definition from one module.

I thought i got the last question right, got 33.7% but i've definitely missed a step if i got half of the correct answer. I have no clue what mess ive made with the free energy question. Kc question just dragged with loads to do.. btw do you know what the right answer was for Kc?

Ah im sure you've got it! :biggrin:

For me, im revising F324 for next week.. im being really optimistic and hopeful and telling myself im going to get really high in that.. wont happen really. OCR will have made an equally wierd paper.

To be honest Rosi, I don't particularly want to speculate on the answers because I could be entirely wrong, the reason I said the last one because it seemed to corroborate with a lot of my friends.

But yeah I'm glad, you know I said to myself if anyone gets an extra mark through my help than it will have been worthwhile, so thanks for telling me that, but I'm sure you would have had it on your own :smile:

I think I would like to do F324 just for fun, no revision, see what I get, but then I'd much rather finish my exams next WEDNESDAY! :biggrin:

Reply 2788

Fallen

17

Original post by Dim0nIX

Can you please specify how on Earth the level of difficulty and the extent of relevance was the same in all 3 papers? Please give me an example of where Chemitry was applied to real-life situations in a "magic tang" manner in Jan 2011/ Jun 2010 papers. And give me an example of a question as challenging as the polymer 3D structure in any of those? Maybe you will be so kind as to point out the 3 long worded essay questions for 7, 9 and 11 marks respectively in previous 2 papers? Or tell me the page number in the book where it talks about the validity of food surveys? I am waiting.

In one of the past papers (maybe Jan 2011?) there was that question on the hair straightening chemical. That was way harder than Magic Tang.

The polymer question was perfectly reasonable, they had basically drawn out the structure of 4,4-bipy for you (they gave you 2,2-bipy) and then you just need to add an ion with 4 water ligands attached. As an A (but not A*) student myself, I can say it was not overly challenging.

The Magic Tang question was tough. I missed the point of it and would be lucky to pick up more than a few marks. At the same time, though, if it was not in their how could they differentiate between me and the A* students? I am okay at chemistry, I will get an A, but I am definitely not talented enough for an A*. That question had to be in there otherwise plenty of people like me would have done, frankly, too well.
All but 1 of the marks in that question was for using the same old formulae in a slightly intelligent manner (which I failed to do). Not beyond the scope of the course, just difficult.

And the long questions were a gift. You say "wordy", but they weren't wordy at all. They were long, but if you have written an essay for it then you completely missed the point.
The last question, most of the marks were for calculation and ionic equations.
The 7 marker was the only question with a significant 'wordy' content, which was 4 definitions and a few diagrams. Being given 4 marks for some definitions is an absolute gift, and they are not very long either.

It was a hard paper, sure. But it is A2 Chemistry (one of the hardest A-levels). What do you expect? It was hard for you, it was hard for me, it was hard for 99% of people. That is why you only need ~65% for an A.

Reply 2789

Medifield

11

It will probs be about 71% for an A. Even though people found it hard, to blow it into perspective the paper followed the spec diligently but just did the questions differently to the legancy and the two new papers. It appears that this paper will discriminate well between the able and less able which is what exam broad want to do. Otherwise how can the correct grade be applied?

It's unfair I know, like for people who studied a lot like me only to find that judegment day had approached :frown:

Anyway, look at it this way, the exam is OVER!! we all have a summer comming up. There is no point of wondering how well you have done- there is no way of changing what you wrote on the paper or you didn't do.

I'm not gonna bother looking at this thread anymore, I still have two more exams comming up that I wish to ace :P
If it's in my fate to end up in clearing or a taking gap year then... so be it. I'll just have to work harder next time.

Good luck all and I hope that you all do well!

(edited 12 years ago)

Original post by Fallen

In one of the past papers (maybe Jan 2011?) there was that question on the hair straightening chemical. That was way harder than Magic Tang.

The polymer question was perfectly reasonable, they had basically drawn out the structure of 4,4-bipy for you (they gave you 2,2-bipy) and then you just need to add an ion with 4 water ligands attached. As an A (but not A*) student myself, I can say it was not overly challenging.

The Magic Tang question was tough. I missed the point of it and would be lucky to pick up more than a few marks. At the same time, though, if it was not in their how could they differentiate between me and the A* students? I am okay at chemistry, I will get an A, but I am definitely not talented enough for an A*. That question had to be in there otherwise plenty of people like me would have done, frankly, too well.
All but 1 of the marks in that question was for using the same old formulae in a slightly intelligent manner (which I failed to do). Not beyond the scope of the course, just difficult.

And the long questions were a gift. You say "wordy", but they weren't wordy at all. They were long, but if you have written an essay for it then you completely missed the point.
The last question, most of the marks were for calculation and ionic equations.
The 7 marker was the only question with a significant 'wordy' content, which was 4 definitions and a few diagrams. Being given 4 marks for some definitions is an absolute gift, and they are not very long either.

It was a hard paper, sure. But it is A2 Chemistry (one of the hardest A-levels). What do you expect? It was hard for you, it was hard for me, it was hard for 99% of people. That is why you only need ~65% for an A.

True, even when I finished and looked around and spoke to my friend behind me I instantly thought, the calculation would have destroyed me everyone else will be fine. On the whole I thought other than the calculations, the paper was robust and tested everything I expected it too, except without a lot of the pH stuff.

I thought however, it was a much harder examination, you cite the fact that in the January 11 paper that there was that hair perming question, with all due respect I would have felt far more comfortable having a stab in the dark on that for 2 marks, than the 6 mark question we got on Magic Tang.

I feel that OCR are yet to get the balance right in terms of questions, I mean fair enough you have to distinguish between the A* candidates, but with grade boundaries been at 61 and 71% respectively, I would have thought that was evidence enough.

Anyway what has happened has happened, doubt I got the 86% UMS I needed, but we will see in the august.

Keep the faith.

Reply 2792

PedalBrain

5

Original post by FruitsPunchSamurai

Do you mind me asking how on earth you get it? access to a paper and enough time to take snaps of each page lol ??

Reply 2793

ramsfan

Original post by PedalBrain

Do you mind me asking how on earth you get it? access to a paper and enough time to take snaps of each page lol ??

Anyone remember what questions 5a, 5b and 6a were worth? please :smile:

Reply 2794

HEC14

if i missed out the state symbols.. will i lose all the marks for the ionic equations? :frown:

Reply 2795

Fallen

17

Original post by haydyb123

True, even when I finished and looked around and spoke to my friend behind me I instantly thought, the calculation would have destroyed me everyone else will be fine. On the whole I thought other than the calculations, the paper was robust and tested everything I expected it too, except without a lot of the pH stuff.

I thought however, it was a much harder examination, you cite the fact that in the January 11 paper that there was that hair perming question, with all due respect I would have felt far more comfortable having a stab in the dark on that for 2 marks, than the 6 mark question we got on Magic Tang.

I feel that OCR are yet to get the balance right in terms of questions, I mean fair enough you have to distinguish between the A* candidates, but with grade boundaries been at 61 and 71% respectively, I would have thought that was evidence enough.

Anyway what has happened has happened, doubt I got the 86% UMS I needed, but we will see in the august.

Keep the faith.

I suppose, but having looked at the solution for the Magic Tang question, 4 or 5 of those marks was just a normal calculation. Just had to have a buffer solution made up to pH = 3.55. I didn't revise properly so didn't get it.
I don't really know what they wanted for "Comment on whether they will get the desired Magic Tang flavour" at the end, but that was only 1 or 2 marks, the same as the perming question.

Wow, sorry you need such a high mark. Good luck!

Reply 2796

Ipcress

6

Original post by Fallen

In one of the past papers (maybe Jan 2011?) there was that question on the hair straightening chemical. That was way harder than Magic Tang.

The polymer question was perfectly reasonable, they had basically drawn out the structure of 4,4-bipy for you (they gave you 2,2-bipy) and then you just need to add an ion with 4 water ligands attached. As an A (but not A*) student myself, I can say it was not overly challenging.

The Magic Tang question was tough. I missed the point of it and would be lucky to pick up more than a few marks. At the same time, though, if it was not in their how could they differentiate between me and the A* students? I am okay at chemistry, I will get an A, but I am definitely not talented enough for an A*. That question had to be in there otherwise plenty of people like me would have done, frankly, too well.
All but 1 of the marks in that question was for using the same old formulae in a slightly intelligent manner (which I failed to do). Not beyond the scope of the course, just difficult.

And the long questions were a gift. You say "wordy", but they weren't wordy at all. They were long, but if you have written an essay for it then you completely missed the point.
The last question, most of the marks were for calculation and ionic equations.
The 7 marker was the only question with a significant 'wordy' content, which was 4 definitions and a few diagrams. Being given 4 marks for some definitions is an absolute gift, and they are not very long either.

It was a hard paper, sure. But it is A2 Chemistry (one of the hardest A-levels). What do you expect? It was hard for you, it was hard for me, it was hard for 99% of people. That is why you only need ~65% for an A.

Just when you think you have the marks - you look at an OCR mark scheme. No scope for interpretation. Just look at January 11 F321 exam there was a halogen question which had a national average of 0.0 students getting the question right. Why because if you wrote halogens are toxic, 0 marks, must specify bromine is toxic. The people that write these papers are out of touch with the real world.

Reply 2797

PedalBrain

5

Original post by ramsfan

Anyone remember what questions 5a, 5b and 6a were worth? please :smile:

FruitsPunchSamurai uploaded the paper. Marks are to the right of each question. I assume there visible

Reply 2798

wilsea05

1

how many marks was the final redox titration question?
and what about questions 5b and d?
5b was the one about water melting and its enthalpy/entropy being positive or negative
5d was about working out the gibbs free energy at 1000k

and finally, how many marks was the long question on rate of Br2? 8?